What is the treatment for an undisplaced proximal 1st metatarsal fracture?

Treatment for Undisplaced Proximal 1st Metatarsal Fracture

The preferred treatment for an undisplaced proximal 1st metatarsal fracture is internal fixation with multiple screws or a sliding screw to prevent displacement, as conservative treatment carries a 30-50% risk of subsequent displacement. 1

Initial Management

• Radiographs should be the initial imaging modality to evaluate the fracture and confirm it is undisplaced 2
• If radiographs are negative but clinical suspicion remains high, MRI is preferred due to its higher sensitivity for detecting small fractures 2
• For immediate pain management, a posterior splint and avoidance of weight-bearing activities should be implemented 3

Definitive Treatment Options

Surgical Management (Preferred)

• Internal fixation with multiple screws or a sliding hip screw is the current preference for undisplaced fractures of the 1st metatarsal 1
• This approach significantly reduces the 30-50% risk of subsequent displacement that occurs with conservative management 1
• Surgical fixation helps maintain proper foot geometry, which is crucial for the 1st metatarsal due to its weight-bearing role 4

Conservative Management (Higher Risk)

• If chosen, conservative management involves:
  • Protected weight bearing in a cast shoe or short leg walking boot for 4-6 weeks 5, 3
  • Regular radiographic follow-up to monitor for displacement 2
  • Transition to rigid-sole shoes after initial immobilization period 3

Special Considerations

• The 1st metatarsal plays a critical role in weight-bearing and gait mechanics - improper healing can lead to significant disability 6
• Malunion in the sagittal plane is a common long-term complication that can result in a non-plantigrade foot 6
• Potential complications include transfer lesions or metatarsalgia if the weight-bearing pattern is altered during healing 2

Follow-up Care

• Regular radiographic assessment at 10-14 days and then at 4-6 weeks to ensure proper healing 2, 3
• Progressive weight bearing should be initiated only after radiographic evidence of healing 3
• Physical therapy may be necessary to restore normal gait mechanics after immobilization 6

Common Pitfalls

• Underestimating the importance of the 1st metatarsal in gait mechanics can lead to long-term disability 6
• Failure to recognize that even undisplaced fractures have a high risk of displacement (30-50%) if treated conservatively 1
• Inadequate immobilization during the healing process can lead to malunion and subsequent foot deformity 6